1. Field of the Invention
This invention relates to an electronic component part with high attaching strength between a ceramic substrate and terminal pin and with high operability, and the method of manufacturing the same.
2. Description of the Related Art Including Information Disclosed Under .sctn..sctn.1.97-1.99:
Known are substrates, such as a resin substrate, metal substrate and ceramic substrate, on which a semiconductor device is formed. Of them, the ceramic substrate is excellent, in a general aspect, over other substrates in terms of its heat dissipation and insulating characteristics and its strength and is extensively employed in the art. Ceramic substrates excellent in their heat conductivity and heat dissipation have recently been developed and there are more and more demands for ceramics substrates.
In the application of the ceramic substrate to the electronic component parts, such as ceramic packages, it is necessary to attach, to a circuit board, terminal pins for external connection. With a recent high integration of semiconductor devices, the size of circuits to be incorporated becomes greater and greater with a corresponding larger increase in the number of terminal pins for the packages. Since a larger integration circuit or circuits are employed for a VLSI including logical circuits (logic VLSI: the number of gates, G&gt;10.sup.5), for example, a larger number of terminal pins are connected to the package. For example, P=200 to 300 for G=10.sup.5. As a multi-terminal pin package use is most often made of semiconductor packages called pin grid array packages. For over 200 terminal pins as in VLSI's, however, the package has to be large-sized so as to arrange the terminal pins.
In order to maintain the conventional package size it will be necessary to arrange the pins in a high density with their size as small as possible in which case the pins have to be strong enough to be detachably connected to an external associated parts. It is also necessary to place the terminal pins in ohmic contact with the conductive layers of the ceramic substrate.
Since the logic VLSI device produces heat as large as 1 to 10 W at the time of operation, the thermal resistance should be made lower than 5.degree. C./W.
As a package with better heat dissipation, attention has recently been paid to a ceramics package composed of Aluminum Nitride (AlN) or silicon Nitride (SiC) ceramic substrate of high thermal conductivity. The ceramic substrate thus employed has 5 to 10 times as great a thermal conductivity as that of the conventional Al.sub.2 O.sub.3 (about 20 W/k.multidot.m) and is useful in view of its freedom from any toxicity as in Beryllium Oxide (BeO).
With high thermal conductivity ceramics, such as AlN and SiC, however, the wettability to the molten metal for connection to the pins is poorer than that of the conventional Al.sub.2 O.sub.3, thus making it difficult to obtain a strong bond to metal terminal pins.